Individual study: Ship rat Rattus rattus eradication on Pein Mal Island, Federated States of Micronesia, Pacific Ocean
Wegmann A., Braun J. & Neugarten R. (2008) Ship rat Rattus rattus eradication on Pein Mal Island, Federated States of Micronesia, Pacific Ocean. Conservation Evidence, 5, 28-32
As part of a larger project attempting to reduce predation pressure from introduced rats Rattus spp. on native fauna and flora on several islands off Pohnpei main island (Pacific Ocean), a rat eradication program was undertaken on the small island of Pein Mal (2.17 ha) where ship rats R.rattus were present. The island was systematically hand-broadcast with rodenticide bait at a pre-determined application rate of 50 kg/ha over one day. Radio-tracking revealed that rats spent a significant amount of time in the forest canopy. Therefore, to ensure that rats living in the canopy had a good chance of encountering bait, bait clusters (bolo baits) were made and catapulted into one third of the palm trees on the island. Mangrove forest surrounds the shore of Pein Mal where rats were also present. Throughout this habitat to ensure rat access to the rodenticide, a bait station grid was established with bait stations nailed to tree trunks approximately 2 m above the high water mark. Pre-bait application trap success (rat captures/trap nights) was 39%. Post-bait application trap success (as recorded 10-14 days after bait application) was 0%. Pre-bait application wax indicator success was 53%. Post-bait application wax indicator success was 0%; subsequent monitoring 6-months later detected no rats. No non-target species appeared adversely effected by the bait.